Method for forming artificial dentures



106. COMPOSITlONS, mu...

' comma 0R PLARTV Sept. 19,1944.

J. F. NELSON ErAL' IETHOD FOR FORMING ARTIFICIAL DENTURES 'Filed lay 26, 1941 FIG.2.

FIGJ.

FIG.3.

IN VENTORS I m W SS 0 as U N A new Y ER 1 .w M 1 Y B :i*: -:u-N1TE| ESTATES PATENT OFFICE f I t ,2",zsa'zso smrnonronronmcanrmrcmn I DENTUBES v 1 g r Joseph F. Nelson, Parsons, Bans, and Henry G. .Nauss, Detroit, Mich, assignors to Kerr Dental Manufacturing Co.,j Detroit, Mich., a corporation of Michigan A .1. L V, nppneetion m'yzs, lfllrs erial No. a ,zs z

r s: Claims. (Chile-55.1)

invention relates to the manufacture of and upper sections of the flask and the mold artificial dentures and more particularly to the formed therein; and

process for forming dentures from synthetic Fig. 5 is an enlarged section of a portion of resins of the acrylic group, such as the methyl the mold after the same has been coated to methacrylates, etc. 7 5 form the impervious surface.

, In the general procedure of forming artificial Generally described, our improved method dentures, an impression is first taken of that follows substantially the procedure which has portion of the oral cavity which is to receive the heretofore been used in the forming of dentures denture. From this a cast is made which is an of the character above described, but with the accurate duplicate of that section of the mouth 1o following differences:

upon which a model of the finished denture is built. A mold is then formed from this model, and the denture material is filled into this mold of the mold which is'impervious to moisture and and cured by a heat treatment. is substantially non-adherent to the denture; 1In the special procedure for forming dentures l5 and I -1 of the material above referred to, the curing is Third, the material employed in making the effected by heat treatment at the temperature mold is modified to in some respects change its of boiling water. It has, however, beenfound characteristics, p ticu y in dimensiona connecessary to protect the acrylic resins from ditrol and increased friability, which latter facilirect contact either with moisture or the plaster 20 tate easy remov l from the denture. of the mold; otherwise the natural pink gum The impervious film on the inner surface of color will become permanently discolored and the mold may be formed in various ways, but the translucency of the material permanently in each not requiring any special skill on the changed to one of cloudiness, thus making the p t o t e cperctcr-v One thod is to inc u e artificial denture unfit for use. Furthermore, 85 in the material from which the mold is formed direct contact between the denture material and an in r ient which will react with another mathe plaster or investment material of the mold terial subsequently applied to the surface of the during the curing process will result in adhesion, mold, to form the impervious film thereon. The so as to render it extremely dimcult or imposlatter material is preferably a liquid which can sible to separate the denture therefrom without 30 be easily brushed r spr y d er he surfaceiniury. Thus, in the past it has been the prac- Various materials may also be employed for tice to line the mold with tin foil so as to form imparting the improved characteristics to the an impervious wall completely isolating the plasmold. We will, however, describe in detail our ter and moisture from contact with the denture mproved method, employin rta n spe ifi material during the curing process. Such proso materials as'follows: 4 cedure is an expensive, tedious and time-cona I suming technique and usually can only be correctly done by one with eonsid m tin-failing lrAn accurate impression A is first taken of the experience, section of the mouth which is to receive the arti- It is the primary object of the invention to 4.0. ficicl denture/using for that Purpose any -4 simplify the process by entirely eliminating the able impre sion m terials h s impr i n tin-foiling operation and substituting therefor a protection which will be equally efiective.

With these objects in view, the invention consists in the method and construction as herein after set forth.

In the drawing:

Fi 1 is a or siongtaken f f figgg gf the impres c mpound ofthe following composition:

Fig. 2 is a similar view showing the cast formed (a) A -binder-Hydrocal D-j-67% by weight; from the impression:

Fig. 3 is a similar view with the cast placed phate-20% y w i in the bottom section of the flask and showing (07 Modifiers-j-powd'ered sugar-43% by weight; the wax denture built thereon; j borlc-acid1% to,2% by weight; sodium "Fig. 4 is a similar view showing both lower acetate-.0570 or more. 1'

Second, a film is formed on the inner surface tic impression compounds of the hydrocolloid types, etc r STEPH Y e v 1? From the impression thus taken, an accurate duplicate B of that section of the mouth is made,

First, the tin-felling step is omitted;

plasters; (b) impression compounds; (0) elas by pouring into the impression material a fluid (b) A film-forming inorganic salt-ferrous un- 1'66? "satiation comma R msuc when the above material has set, an exact wax-duplicate C of the flnished denture is built upon it in the usual way, with the teeth D in their proper positions.

S-rnrIV SrsrV The top section F of the flask is next fltted upon the bottom section E, and this section is then carefully filled with the same plaster compound as is Step II. The cover G of the flask is then tightly fltted upon the section F, allowing an excess of plaster to escape through the holes H in said cover. Time is then allowed for the compound in the flask to thoroughly set.

Srrr VI The entire flask is now placed in boiling water for about ten minutes, in order to thoroughly soften or melt the wax-duplicate of the flnished denture. The flask is then separated into its two sections at the junction I of the bottom and top sections of the flask, and the soft melted wax completely washed out with boilina water.

Bra? VII The lingual surfaces of the mold for the flnished denture in the top section of the flask are lightly painted with a liquid J (Fig. said liquid being of the following composition:

(a) A film-forming inorganic salt-sodium silicate solution-1 fluid ounce (b) Modifiers- Liquid dryerfluid dram Disodium phosphate-19 grains Distilled water-3 to 4 c. c.

SmVIII H The palate surfaces of the flnished denture in the bottom section of the flask are lightly painted with the same liquid.

Sm IX Suflicient soft denture material is now packed into the mold of the completely replace the space originally occupied by the temporary wax denture and which was removed by the boiling water. All sections of the curing flask are then fitted together and the complete mold placed into a clamp and tightly closed so as to squeeze out all of the excess denture material. Within the mold all surfaces of the denture material are completely isolated from direct contact with the plaster surfaces and the moisture in the plaster. The tightly clamped flask is then submerged in boiling water for approximately thirty to sixty minutes, the denture material being cured during the heating period Sue K After the denture material in the flask has been subjected to the heat of the boiling wata' for a sufllcient length of time to cure it, the flask is removed from the hot water and placed in the cold water for about fifteen minutes, or until cool. It is then opened and the mold carefully broken away from the flnished denture. Due to the friable nature of the mold compound, this removal 1..

top section of the flask to CROSS REFERENCE Examiner is easily accomplished without injury to the denture.

The speciflc materials and the precise proportions above specified are not essential and may 5 be varied without departing from the spirit of our invention. Also, the steps as above given may be varied. However, the essential features are:

First, that the surfaces of the mold which come in contact with the denture should be formed with a fllm which is impervious to moisture;

Second, that this fllm should be relatively nonadherent to the denture material; and

Third, that the mold should be relatively friable while nevertheless possessing suflicient rigidity to accurately reproduce in the denture the form of the wax pattern.

More broadly described, the denture investment powder contains:

(a) A binder which sets hard when mixed with 2 water such as-plaster of Paris, Hydrocals,

cements (Portland or high alumina cements), etc. (1)) Inorganic or organic materials which have film-forming properties either when used 26 alone or in combination with other filmforming solutions. Such materials may be as follows-powdered glue or gelatin, powdered casein or albumin, aluminum or cal-- cium stearates, ammonium stearate, alumi- 30 num acetate, alum, ferrous sulphate, magnesium fluosilicate, or salts of aluminum, iron, copper, antimony, tin and chromium. (c) Modifiers-which change or control the set-' ting time of the investment-mix or control the consistency and flowing qualities of the investment mix, thus facilitating accurate reproductions of the impression. Such modifiers may be either organic or inorganic materials, such as: sodium acetate, sugar, dextrin, boric acid, borax, etc.

Some other specific formulae are as follows:

. Formula No. 2 A. Denture investment powder contains: a Bill d1$' Hydrocal D or plaster of Psris90-95% by weight (b) Film-forming materials (inorganie) White Portland cement or white alumina cem'ent-6l0% Aluminum or calcium hydroxide-0.57 47}, (c) Modiflers- Anhydrous potassium carbonate-0.054% F. Painting liquid:

50 (o) Film-forming inorganic salt Solution of magnesium fluo silicate-m B.

Formula No. 3 L Denture investment powder contains:

(a) Binder-- a Hydrocal plaster or plaster of Paris% by weight (b) Film-forming materials (organic)- Powdered glue or gelatin-l-10% (c) Modifiers- Gypsum rock--0.l%-2% Alum-0.l%-0.5% B. Painting liquid:

(a) Solvent- Water (b) Film-forming materials-- 7 otsssium biehromate or cbrcme'alum or tannic acid-5%.

to saturated solution in the water .Filmiormedistben exposed tosunligbt ioraiew minutes.

I Formula No. 4 a A. 183mg: iggestment powder contains: d (Hydrocal plaster or plaster of Paris)-98% (b) Film-forming materials (organic)- Powdered albumin or caseinl%-10% (c) Modifiersyps'um rock-0.1%2%

1 7 57 Calcium oxide or cauticsoda- 0.5%-2% B. Painting liquid:

(a) Solvent- Water-800 c. c.

(a) Film-forming matuial- Formaldehyde solution 407 -40-50 0. 0., or Plgfium humanism-5% to saturated solution in the Formula No. 5

A. l()e)ntiredinvestment powder contains:

a in er- Hydrocal plaster or plaster of Paris-797,489, by weigh White alumina cement-+10% (b) Film-forming material- Aluminum acetate-0. 5%-S% ypsum rock0.5%2% Soluble sodium silica e ry pWd.)0.1-2% B. Painting liquid:

() Solvent Water-l3 gallons. (b) Film-forming material (organic)- Soap-5 lbs.

It is not absolutely necessary that one of the film-forming materials should be placed in the investment powder. It is only necessary that one of the materials should be in liquid form so that it can he painted over the surface to be protected and that the other material should be brought in contact with the first. For instance, the two materials which react upon each other can be placed in separate liquids which are successively painted or otherwise applied to the surface of the mold to be protected, thereby forming on said surface a heat-resistant, moisture-impervious film.

What we claim as our invention is:

1. In a process of forming dentures, the steps of incorporating in the mold-forming material one ingredient for forming a moisture-impervious film, forming a denture mold of such material, and coating the inner surface of said mold with a liquid which reacts with the incorporated material to form an impervious film.

2. In a process of forming dentures, the steps of forming a denture mold of a relatively friable material including a chemical reagent, and coating the inner surfaces of said mold with a liquid which reacts with said chemical reagent to form in said surfaces a moisture-impervious film.

3. In a process of forming dentures, the steps of forming a denture mold of a relatively friable material including a chemical reagent, and coating the inner surfaces of said mold with a liquid which reacts with said chemical reagent to form in said surfaces a moisture-impervious film and one which will be substantially nonadherent to the denture.

4. In a process of forming dentures, the steps of incorporating in the mold-forming material an inorganic salt, forming a denture mold of such material, and coating the inner surface of said mold with a liquid which reacts with said salt to form an impervious film,

5. In a process of forming dentures, the steps of incorporating in the mold-forming material a quantity of ferrous sulphate, forming a denture mold of such material, and coating the inner surface of said mold with sodium silicate solution which reacts with said ferrous sulphate to form an impervious film.

6. In a process of forming dentures, the steps of forming a mold of the following compound substantially in the proportion specified:

Per cent Hydrocal D 67 Ferrous sulphate 20 Powdered sugar 13 Boric acid 1 t0 2 Sodium acetate .05

coating the inner surface of said mold with a liquid comprising:

Sodium silicate solution fiu. oz 1 Liquid dryer fiu. dr /2 Disodium phosphate gr 19 Distilled water c.c 3 to 4 JOSEPH F. NELSON. HENRY G. NAUSS. 

